The numerical methods for compressible turbulent boundary layer developed to date are not applicable to turbulent transonic viscous-inviscid interactions because they assume the known pressure distribution. For supersonic laminar flow, the interaction problems have been studied by using integral method (e.g. LEES and REEVES). For supersonic separated and reattaching turbulent flow and turbulent wake, their method has been extended by HUNTER and KINEBERG respectively. The latter methods are not applicable to attached turbulent flow which is not of wake-like character and for which there are no similar solutions. For that purpose, an integral boundary-layer method is extended and relevant similar solutions are developed. The solutions are verified by comparing the velocity distributions in the boundary layer with experiments. The author's integral method is justified by comparing the shape factor and other characteristics with those for the attached turbulent boundary layer on the wall of a transonic wind tunnel measured by ALBER.
An experimental investigation of a stacked plasma generator of MAECKER type has been performed at low pressures (25-760Torr) and low electric currents (10-60A) for argon gas. Radial distributions of electron density and electron temperature were obtained by measuring the intensities of spectral lines and continuum from cylindrically confined plasmas. Based on such data of the macroscopic plasma parameters, the SAHA equilibrium relation, and the collisional and radiative theory of BATES et al., the spatial extent of equilibrium region and nonequilibrium effects of electronic excitation of the atom have been examined. In the plasmas generated in the apparatus, electron temperature ranged from 7, 500 to 11, 000°K and electron density 7×1014 to 3×1016cm-3. It was found that thermochemical equilibrium conditions existed only in the vicinity of the tube axis even at relatively high pressures and high currents, and the higher excited levels than the 5p level of argon atom were always in SAHA equilibrium with free electrons.
Starting at a point inside a nozzle, we performed the calculation of underexpanded sonic jets through two-dimensional convergent nozzles with flat wall by taking a sonic line into consideration and the effect of the convergence angle on those jets were investigated in all the range of the angles which can be used for practical purpose under various nozzle exit conditions. The flowfield inside the nozzles was solved by a direct method and an especial attention was paid to the meaning of the boundary conditions on the inlet and the exit side of nozzles. We obtained the shape of the sonic line and the jet boundary along with the location of the shock wave analytically and experimentally and both the results are in a reasonable agreement.
Carbon-fiber reinforced plastics (CFRP) manufactured by the filament-winding (FW) technique have been in use in pressure vessels such as rocket motor cases. The present paper including the following one treats of the optimum design of FW pressure vessels. First, the experimental results on stress and strain distributions of CFRP FW pressure vessels are compared with the numerical results obtained by F.E.M. and a good agreement is shown to exist between them. Secondly, referring to these evidences, the optimal dome shapes are proposed based on some kinds of failure criteria and the lamination theory, compared with the isotensoid surface. In addition, the optimal lamination ratio of the helically wound layer and the circumferencially wound layer in cylindrical part is proposed.
The present paper treats of the optimum design of carbon-fiber reinforced filament-wound pressure vessels when used as rocket motor case. That is, the dome shape and the constitution of lamination are optimized so as to maximize the performance coefficient of rocket motor without failure. The dome shape is expressed by a power series or a cubic spline function and the optimization is done by using a simplex method or DAVIDON-FLETCHER-POWELL method. The analytical results show that the helically wound pressure vessels are needed to be stiffened in the regions near the opening and near the cylindrical part. The pressure vessels with stiffened layers have 20 percent higher performance coefficient compared with those without them.
A multi-spark camera of a pulse-control type has been constructed. Typical performance of the camera is as follows: number of frames=24, maximum framing rate=1×106 frames/s, full width at half-maximum duration of a light pulse =0.4μs, maximum energy of discharge capacitor=2 joules, light sourced dimension=1mm, and static spacial resolution=6lines/mm. Several examples of photography using the camera have been included, related to a flyer impact test, fracture shadowgraphy of a polymeric material and water eruption due to an under-water spark.